How many studies support Zinc?

An updated Cochrane review found zinc can reduce the duration of common cold symptoms when started within 24 hours of onset, a finding consistent with an earlier Cochrane review and supportive systematic reviews, though the benefit is modest and dosing/formulation dependent. That's backed by 10 published studies in Vitaebase's database, including 1 randomized controlled trial and 7 meta-analyses, the most recent from 2024 -- a fairly substantial body of research for a single topic.